Evaluating the Psychometric Properties of the Psychological Capital Questionnaire (PCQ) in Patients with Parkinson's Disease.

Background: Positive personality resources have demonstrated the ability to positively impact health outcomes.

Objective: To examine the psychometric properties of the original Psychological Capital Questionnaire (PCQ-24) in patients with Parkinson's disease (PD).

Methods: A sample of 114 individuals with PD completed the PCQ-24, and via a latent factor modeling framework exploratory and confirmatory factor analyses were conducted to evaluate the psychometric properties in people with PD.

Results: Exploratory factor analysis (EFA) revealed that both the efficacy and hope scales were reliable (Cronbach's alpha = 0.87 and 0.86, respectively) and had statistically acceptable validity with strong factor loadings all above the practical threshold of 0.60. The resilience and optimism scales were also reliable (Cronbach's alpha = 0.78 and 0.73, respectively) but had only moderately acceptable validity in part due to three reverse-scored items (i.e., No. 13, 20, & 23) with weak factor loadings of 0.26, 0.46, and 0.50, respectively. After excluding these at-risk items, the overall factor loadings for resilience and optimism were significantly improved at the acceptable above 0.60. The CFA results confirm a statistically acceptable model fit for the modified version (only 21-items) of the PCQ in the PD sample.

Conclusion: Both EFA and CFA analyses provide statistical evidence supporting the modified PCQ version and demonstrate better test validity and reliability for the PD population. The refined PCQ form is both effectively shorter and psychometrically superior to the original and has promise in investigating health outcomes in people with PD.